1. Field of the Invention
The present invention relates to an elevator door control apparatus, and more particularly, to an elevator door control apparatus for not only increasing safety to users in opening and closing motions of an elevator door, but also making it easy to perform door speed adjustment at installation.
2. Description of the Related Art
FIG. 1 is a block diagram showing internal construction of this type of elevator door control apparatus, and FIGS. 2 to 4 show waveforms of door closing motions. In FIG. 1, reference numeral (hereinafter: numeral) 1 represents an elevator control panel, and numeral 2 an I/O port where a door open command is inputted from the elevator control panel 1. Further, numeral 3 represents a ROM saving operation programs for a CPU 4 and several sorts of predetermined motor speed commands beforehand, and numeral 4 the CPU controlling internal operations of the elevator door control apparatus. Furthermore, numeral 5 represents a pulse width modulation (PWM) unit converting a PWM command inputted by the CPU 4 into a gate signal, numeral 6 a gate signal generator driving a below-mentioned power circuit 7 based on the gate signal from the PWM unit 5, and numeral 7 the power circuit 7 for driving motor 8 represents. Moreover, numeral 8 the motor, numeral 9 a pulse encoder attached to the motor 8, and numeral 10 a pulse count unit counting output pulses from the pulse encoder 9. In addition, numeral 11 represents a RAM saving calculation results of the CPU 4 and various data, numeral 12 a power supply, numeral 13 a display unit providing various displays to a user, and numeral 14 a speed adjustment set pin for switching speed command values that are saved in the ROM 3 and read by the CPU 4.
Next, using FIGS. 1 to 4, known control of door closing motions will be described. When a door close command is generated by the elevator control panel 1, the command is read into the I/O port 2, and, according to this door close command, a motor speed command, as represented by reference waveform (hereinafter: waveform) 1a in FIG. 2, is read from the ROM 3 into the CPU 4. Here, by the motor speed command, the pulse count unit 10 counts output pulses from the pulse encoder 9 attached to the motor 8, and the counted value is sent to the CPU 4. Then, the CPU 4 calculates the position of a door from the counted value to read an adequate motor speed command value from the ROM 3 using the positional information. In addition, the motor speed command value read from the ROM 3 can also be switched by the speed adjustment set pin 14.
The CPU 4 obtains a torque command value, as represented by code 3a in FIG. 4, that is calculated from the speed difference between the motor speed command value read from the ROM 3 and an actual motor speed which is obtained from the counted value outputted from the pulse count unit 10 and is represented by code 2a in FIG. 3, and that is necessary to make the motor follow the motor speed command value. Further, the CPU 4 sends a PWM command corresponding to this torque command to the PWM unit 5, which converts it into a gate signal, and the power circuit 7 is driven by a command outputted from the gate signal generator 6 receiving this gate signal. Furthermore, the power circuit 7 drives the motor 8, so the rotation speed of the motor 8 follows the motor speed command value.
Regarding the above-mentioned door closing motion, door closing energy is regulated by national regulations (ASME 112.4 or BS 2655 Part 1 2.7.2, and the like). The door closing energy can be obtained by door weight and door speed as shown in equation (1). EQU Door Closing Energy={(Door Weight)/(2.times.(Gravitational Acceleration))}.times.(Door Speed).sup.2 ( 1)
Then, in order to meet the standard values of the national regulations, it is necessary to change the door speed, that is, a motor speed according to the door weight. However, sizes and materials of doors vary since elevator specifications are different in every building. Presently, installers calculate door weight from door specifications and perform speed adjustment at sites.
As a supplementary explanation regarding the door closing energy, the door speed is an average door closing speed, which is also clearly written in the national regulations. Specifically, door speed is obtained from the following equation (2). EQU Average Door Closing Speed=(Moving Distance from a fully Opened Position to a fully Closed Position)/(Run Time) (2)
In addition, the run time is defined, for example, as the time required for running through the distance that is the result of subtraction of 25 mm from each distance between the fully opened and fully closed positions, in case of a parting-from-center door. For more specific explanation, referring to FIG. 5, if the door speed is the value represented by waveform 4a in FIG. 5, the partition t1 in FIG. 5 corresponds to the part being 25 mm distant from the fully opened position, and partition t2 corresponds to the part being 25 mm distant from the fully closed position. Hence, the running time in this case corresponds to the partition T1 between the partitions t1 and t2.
As described above, in the door closing motion, there are regulations on the door closing energy, and the known art has a problem of requiring significant man-power for establishing the of weight of every door at all sites, and for adjustment of door speeds for every door.
In addition, another problem is that, as described above, door weight is calculated by installers, and hence, there are possibilities of calculating an erroneous door weight due to human errors.
Moreover, an additional problem on the contents of speed control is that, as understood from the definition of the average door closing speed, it is not determined as the speed adjustment corresponding to the door closing energy even if closing time is changed by adjusting the speeds only near the fully opened and fully closed positions.